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Biomedical subjects

G Freyss

Publications and source records attributed to G Freyss.

At least 19 recordsLinked to original sources
PubMed1992

[Surgical landmarks of the temporo-frontal branch of the facial nerve].

The temporal branches of the facial nerve, and in particular the rami for the frontalis muscle, have been the subject of many studies with the main objective of avoiding injury. The usual reference points, sometimes difficult to localise, anatomical variations in their branching and anastomoses are the main points of our investigation. This anatomical dissection study of 30 cadavres, with easy reference points available both superficially and in the depths allow a simple, non complicated localisation of the frontal branch and its anastomosis in a precise way on the mandibular condyle, the zygomatic arch and the temporal region. The distances described a, b, c, are useful in common surgical practice: temporo-mandibular joint surgery, facial lifting, temporal and temporo-parietal fascia flaps, and contralateral neurotomy for frontal symmetrization among others.

Dissection↗
PubMed1992

[Vestibular studies: current status, prospects].

Equilibrium is based on gaze stabilization. Clinical examinations currently test, individually the three components involved in equilibrium: vestibular, visual and proprioception. New investigations are being developed to test equilibrium dynamic conditions. After briefly reviewing vestibular physiology, under the authors discuss the various tests of vestibular function and equilibrium.

Eye Movements↗
PubMed1991

[Diagnostic strategy of acoustic neuroma. Evaluation of efficacy of auditory evoked potentials. Apropos of a series of 50 neuroma cases].

The authors carry out a retrospective study of the diagnostic procedures used in a series of 50 acoustic neuromas. AEP were performed for thirty-four neuromas at some stage of their history. The findings were perfectly normal for eight of them, which represents a sensitivity level of 76%. Various elements likely to account for this are put forward, then the role of AEP and MRI in the diagnostic strategy for neuroma is discussed in the light of this study. Finally, the authors emphasize the necessity to regularly evaluate the diagnostic methods in order to guarantee their quality and reliability.

Evoked Potentials, Auditory↗
PubMed1991

[Evaluation of the prognosis of facial paralysis after surgery of acoustic neurinoma by an early Hilger's test].

Surgery for acoustic neuroma is highly risky for the facial nerve. This is why we have tried to assess immediate postoperative facial impairment by performing Hilger's test within the first few hours. Further evolution of the facial function showed the predictive value of Hilger's test as regards facial recovery. Indeed, a difference greater than 2 mA as compared with the opposite side indicates a lack of facial recovery at the 3rd postoperative month. In addition, facial muscle testing performed within the first postoperative 72 hours makes the prognosis of facial function recovery possible. Lack of facial recovery at the 3rd postoperative month was observed for neuromas with a diameter exceeding 2 cm. Preoperative assessment of the risk of facial sequellae is fundamental and essentially depends on the size of the tumor and on the surgical approach. Intraoperative facial monitoring allows better ensuring the preservation of the VIIth cranial nerve and consequently improves postoperative function.

Electric Stimulation↗
PubMed1991

[Bone augmentation in implant surgery].

The authors experience on twelve patients in the field of bone grafting prior to implant surgery is presented. The technique employed depends largely on the anatomical location of bone insufficiency, such as: 1) Where there is not enough bone beneath sinus locations, grafting with cancellous iliac bone blended with coral particles is suggested. 2) Where the jaw is not sufficiently thick, such as in the incisor-cuspid regions, the authors employ cancellous and/or cortical bone grafts. 3) Horizontal osteotomy and interposition of cortical-cancellous bone graft is proposed where there is a lack of bone height in the incisor-cuspid regions. The results of the various techniques are analysed from a clinical, radiographic and histologic perspective. Twelve patients have been treated with 2 years follow-up.

Adult↗
PubMed1990

[Vestibular compensation. Review of the literature and clinical applications].

Vestibular compensation is an excellent model for the study of plasticity of the adult central nervous system. Therefore it has been the subject of several studies in humans and animals, which will be briefly summed up by the authors. Lesions of the labyrinth or vestibular neurectomy are immediately followed of postural and oculomotor disorders, as well as by dynamic deficits of the various vestibular reflexes (vestibulo-ocular and vestibulonucal reflexes). While the former problems always recede in all species, the restoration of the dynamic properties of vestibular reflexes largely depends upon the species considered, in particular for the vestibulo-ocular reflex. However, this function seems to recover the gain and phase it had prior to the lesion in both humans and monkeys. What is the neuronal substrate of these various deficits? Electrophysiological studies have demonstrated at the acute stage a symmetrical activity between the two vestibular nuclei: on the side of the lesion, the nucleus becomes inactive, while the resting discharge of the contralateral vestibular neurons is increased. Following compensation, symmetric activity is restored between both nuclei due to the regeneration of a new basic discharge in the deafferented neurons. The matter of vestibular compensation can therefore be formulated as follows: which mechanisms enable a central neuron inactivated du to the suppression of most of its excitatory afferences to recover a normal spontaneous activity? Several hypotheses, either pre- or postsynaptic, are currently put forward. Presynaptic hypotheses consider the role of the various afferences of the vestibular nuclei, ie. visual, proprioceptive, commissural, cerebellar and other afferences. In fact, the vestibular nuclei are not merely relays between the labyrinthine receptors and the nuclei of the oculomotor nerves, but actually form real sensorimotor integration centers. Besides the afferences from the vestibular nerve, they receive several other sorts of information, including visual and spinal proprioceptive inputs. An increase in the activity of these afferences, a sprouting of their axon collaterals, may favor the return to a normal basic discharge of the central vestibular neurons. The postsynaptic hypotheses involve either a change in the intrinsic membrane properties of the central vestibular neurons following the lesion, or an increase in the number of receptors located on their surface. More specifically, denervation supersensitivity of the glutamatergic receptors has been put forward as the possible origin of vestibular compensation.

Afferent Pathways↗
PubMed1989

[Benign paroxysmal positional vertigo and provocative maneuvers].

Main features of the benign paroxysmal positional vertigo (B.P.P.V.) are: latency before the onset of vertigo, nystagmus of the rotatory type beating toward the lower ear, nystagmus tires out, nystagmus gets inverted when the head is brought back to orthostatism, nystagmus is reproducible as many times as the position is taken. B.P.P.V. is due to a deposit of heavy material on the cupula of the posterior semi circular canal. In this unusual condition, the cupula moves under the effect of gravity acceleration. The goal of the treatment is to free the cupula. The manoeuvre consists after determination of the position that elicits the vertigo to move the whole head and body together of the patient to a 180 degree opposite position in which the addition to the endolymph flow forces and weight forces of the material will unstick it from the cupula. The positive result of the manoeuvre is instantly proved by the arising of a rotatory nystagmus beating again toward the sick ear. In other words it is not the inversion of the primary nystagmus but a nystagmus beating the same direction. This is explained by the dynamic of the cupula: in the prime position the density modified cupula moves toward the canal. At the end of the manoeuvre when the velocity of the head is zero, the cupula has to support different forces. First the addition of the endolymph flow forces and the inertia of the heavy material makes the cupula move toward the ampulla. Secondly when the superficial tension forces are too high the heavy material unstick from the cupula and it goes back to its normal position. En this very moment the cupula moves toward the canal. The results are of more than 90% positive in one ore two sessions 4,2% of recurrence. The manoeuvre is unsuccessful in spontaneous nystagmus revealed by a position, in torsional nystagmus as in fistulas or in central position nystagmus.

Humans↗
PubMed1988

[Anatomical and functional evaluation, after 3 and 5 years, of 94 cases of chronic cholesteatomatous otitis media. Clinical and therapeutic implications].

Anatomic and functional results are reported after 3 and 5 year follow up of 94 cases of chronic cholesteatomatous otitis operated upon and kept under surveillance by the same surgeon between 1975 and 1983. Open technics dominated and were justified by seven clinical and epidemiologic factors found alone or in combination in 80% of patients. Results must allow for the high rate of non-attenders (40% at 3 years and 70% at 5 years). Recovery from their cholesteatoma was obtained in 84 and 78% of patients after 3 and 5 years respectively, 52% recovering useful hearing, 2 out of 3 of these due to an open technic. Modified radical mastoidectomy is considered to be undoubtedly the most effective treatment for this type of affection.

Adolescent↗
PubMed1988

[Anatomical and functional evaluation 3 and 5 years later of 94 cases of chronic cholesteatomatous otitis media. Clinical and therapeutic implications].

Anatomical and functional results were evaluated at 3 and 5 years after surgery for chronic cholesteatomatous otitis media in 94 patients treated by the same surgeon between 1975 and 1983. Open techniques predominated and were justified by seven clinical or epidemiologic factors present alone or in association in 80% of cases. Many patients were non-attenders at follow up (40% at 3 years and 70% at 5 years), recovery from their cholesteatoma being noted in 84% and 78% of those attending at 3 and 5 years respectively. Useful audition was recovered in 52%, including 2 of 3 due to an open technique. Petro-mastoid hollow-out with arrangement of cavity and minimal ossicular reconstruction is considered the most effective treatment for this type of affection.

Adolescent↗
PubMed1985

[Labial incompetence and maxillodental dysmorphosis].

A definition of labial incompetence is given and emptrasis placed on the fact that this is a symptom of maxillodental dysmorphism (MDD) and not of nasal dyspermeability. Pathogenic features are discussed, the relevant clinical and paraclinical diagnostic features of MDD outlined, and the different alveolodental and/or bony (maxillary or mandibular) dysmorphias responsible for labial incompetence described. Principles of orthodontic and surgical treatment are centered on re-establishment of a correct articulation and therefore labial competence.

Alveolar Process↗
PubMed1985

[Mucoceles of the maxillary sinus. Diagnostic and therapeutic problems. Apropos of 5 cases].

Five cases of the rarely observed maxillary sinus mucocele are reported, one patient with bilateral lesions presenting primary dilatation of the bronchi. A previous history of surgery or injury to sinuses was obtained in all cases, the diagnosis being confirmed by computed tomography imaging. Recovery is usually complete after the Caldwell-Luc operation. One case with exclusion of the sinus is described and the literature reviewed.

Adult↗